import java.util.LinkedList;
import java.util.Queue;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * user:likai
 * Date:2023-01-13
 * Time:18:59
 */
public class BinaryTree {

    static class TreeNode {
        public char val;
        public TreeNode left;//左孩子的引用
        public TreeNode right;//右孩子的引用

        public TreeNode(char val) {
            this.val = val;
        }
    }


    /**
     * 创建一棵二叉树 返回这棵树的根节点
     *
     * @return
     */
    public TreeNode createTree() {
        TreeNode nodeA=new TreeNode('A');
        TreeNode nodeB=new TreeNode('B');
        TreeNode nodeC=new TreeNode('C');
        TreeNode nodeD=new TreeNode('D');
        TreeNode nodeE=new TreeNode('E');
        TreeNode nodeF=new TreeNode('F');
        TreeNode nodeG=new TreeNode('G');
        TreeNode nodeH=new TreeNode('H');
        nodeA.left=nodeB;
        nodeA.right=nodeC;
        nodeB.left=nodeD;
        nodeB.right=nodeE;
        nodeC.left=nodeF;
        nodeC.right=nodeG;
        nodeE.right=nodeH;
        return nodeA;
    }

    // 前序遍历
    public void preOrder(TreeNode root) {
        if(root==null){
            return;
        }
        System.out.print(root.val+" ");
        preOrder(root.left);
        preOrder(root.right);
    }

    // 中序遍历
    void inOrder(TreeNode root) {
        if(root==null){
            return;
        }
        inOrder(root.left);
        System.out.println(root.val+" ");
        inOrder(root.right);

    }

    // 后序遍历
    void postOrder(TreeNode root) {
        if(root==null){
            return;
        }
        postOrder(root.left);
        postOrder(root.right);
        System.out.println(root.val+" ");
    }

    public static int nodeSize;

    /**
     * 获取树中节点的个数：遍历思路
     */
    void size(TreeNode root) {
        if(root==null){
            return;
        }
        nodeSize++;
        size(root.left);
        size(root.right);
    }

    /**
     * 获取节点的个数：子问题的思路
     *
     * @param root
     * @return
     */
    int size2(TreeNode root) {
        if(root==null){
            return 0;
        }
        return size2(root.right)+size2(root.left)+1;
    }


    /*
     获取叶子节点的个数：遍历思路
     */
    public static int leafSize = 0;

    void getLeafNodeCount1(TreeNode root) {
        if(root==null){
            return;
        }
        if(root.left==null&&root.right==null){
            leafSize++;
        }else{
            getLeafNodeCount1(root.left);
            getLeafNodeCount1(root.right);
        }
    }

    /*
     获取叶子节点的个数：子问题
     */
    int getLeafNodeCount2(TreeNode root) {
        if(root==null){
            return 0;
        }
        if(root.left==null&&root.right==null){
            return 1;
        }
        return getLeafNodeCount2(root.left)+getLeafNodeCount2(root.right);
    }

    /*
    获取第K层节点的个数
     */
    int getKLevelNodeCount(TreeNode root, int k) {
        if(root==null||k<=0){
            return 0;
        }
        if(k==1){
            return 1;
        }
        return getKLevelNodeCount(root.left,k-1)+getKLevelNodeCount(root.right,k-1);
    }

    /*
     获取二叉树的高度
     时间复杂度：O(N)
     */
    int getHeight(TreeNode root) {
        if(root==null){
            return 0;
        }
        int left=getHeight(root.left);
        int right=getHeight(root.right);
        int max=left>right?left:right;
        return max+1;
    }


    // 检测值为value的元素是否存在
    TreeNode find(TreeNode root, char val) {
        if(root==null){
            return null;
        }
        if(root.val==val){
            return root;
        }else {
            if (root.left != null) {
                if (find(root.left, val) != null) {
                    return root.left;
                }
            }
            if (root.right != null) {
                if (find(root.right, val) != null) {
                    return root.right;
                }
            }
        }
        return null;
    }

    //层序遍历
    public static Queue<TreeNode> queue=new LinkedList<>();
    public static void levelOrder(TreeNode root){
        queue.offer(root);
        while(!queue.isEmpty()){
            System.out.print(queue.peek().val);
            TreeNode cur=queue.peek();
            if(cur.left!=null){
                queue.offer(cur.left);
            }
            if(cur.right!=null){
                queue.offer(cur.right);
            }
            queue.poll();
        }
    }

    // 判断一棵树是不是完全二叉树
    boolean isCompleteTree(TreeNode root) {
        if(root==null){
            return true;
        }
        Queue<TreeNode> queue=new LinkedList<>();
        queue.offer(root);
        while(!queue.isEmpty()) {
            for (int i = 0; i < queue.size(); i++) {
                TreeNode node = queue.poll();
                if (node == null) {
                    if (!queue.isEmpty()) {
                        return false;
                    }else {
                        return true;
                    }
                }
                queue.offer(node.left);
                queue.offer(node.right);
            }
        }
        return true;
    }

    public static void main(String[] args) {
        BinaryTree binaryTree=new BinaryTree();
        TreeNode A=binaryTree.createTree();
//        binaryTree.size(A);
//        System.out.println(BinaryTree.nodeSize);
//        System.out.println(binaryTree.size2(A));
//        binaryTree.getLeafNodeCount1(A);
//        System.out.println(BinaryTree.leafSize);
        System.out.println(binaryTree.isCompleteTree(A));
    }
}
